<template>
  <div class="goods">
  	<div class="mennu-wrapper" ref="mennuWrapper">
  	  <ul>
  	  	 <li v-for="(item,index) in goods" class="menu-item" :class="{'current': currentIndex===index}"
         @click="selectMenu(index,$event)" ref="menuList">
  	  	  <span class="text border-1px">
  	  	  	<span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>
  	  	  	{{item.name}}
  	  	  </span>
  	  	</li>
  	  </ul>
  	</div>
  	<div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li v-for="item in goods" class="food-list" ref="foodList">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li v-for="food in item.foods" class="food-item border-1px">
              <div class="icon">
                <img widtn="57" height="57" :src="food.icon">
              </div>
              <div class="content">
                <h2 class="name">{{food.name}}</h2>
                <p class="desc">{{food.description}}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}</span>
                  <span>好评率{{food.rating}}</span>
                </div>
                <div class="price">
                  <span class="now">￥{{food.price}}</span>
                  <span class="old" v-show="food.oldPrice">￥{{food.oldPrice}}</span>
                </div>
              <div class="cartcontrol-wrapper">
                <cartcontrol :food="food"></cartcontrol>
              </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>

    <shopcart  ref="shopcart" :select-foods="selectFoods" :deliveryPrice="seller.deliveryPrice" :minPrice="seller.minPrice"></shopcart>
  </div>
</template>

<script type="text/ecmascript-6">
  import BScroll from 'better-scroll';
  import shopcart from 'components/shopcart/shopcart';
  import cartcontrol from 'components/cartcontrol/cartcontrol';

  const ERR_OK = 0;

  export default{
  	props: {
  	  seller: {
  	  	type: Object
  	  }
  	}, 
  	data() {
  	  return{
  	  	goods: [],
        listHeight: [],
        scrollY: 0
  	  };
  	},
    computed: {
      currentIndex() {
        for (let i = 0; i < this.listHeight.length; i++) {
          let height1 = this.listHeight[i];
          let height2 = this.listHeight[i + 1];
          if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
            return i;
          }
        }
        return 0;
      },
      selectFoods() {
        let foods = [];
        this.goods.forEach((good) => {
          good.foods.forEach((food) => {
            if(food.count) {
              foods.push(food);
            }
          });
        });
        return foods;
      }
    },
  	created() {
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];

      this.$http.get('/api/goods').then((response) => {
        response = response.body;
        if(response.errno === ERR_OK){
        	this.goods = response.data;
          //DOM真正发生变化实在nextTick回调之后
          //nextTick保证DOM已经渲染完成
          this.$nextTick(() => {
            this._initScroll();
            this._calculateHeight();
          });  
        }
      });
  	},
    methods: {
      selectMenu(index,event) {
        //如果不是自定义事件，将return
        if(!event._constructed){
          return;
        }
        //根据menu的index找到food所在位置
        let foodList = this.$refs.foodList;
        let el = foodList[index];
        this.foodsScroll.scrollToElement(el, 300);//定义动画时间为300毫秒
      },
      _drop(target) {
         // 体验优化,异步执行下落动画
        this.$nextTick(() => {
          //访问子组件shopcart的drop()方法
          this.$refs.shopcart.drop(target);
        });
      },
      _initScroll() {
        this.menuScroll = new BScroll(this.$refs.mennuWrapper,{
          //'better-scroll'监听了touchSrart，touchEnd事件，阻止了默认事件
          //初始化'better-scroll'需要添加属性
          click:true
        });
        this.foodsScroll = new BScroll(this.$refs.foodsWrapper,{
          click:true,
          probeType:3 //无论何种滚动，都能实时监测到位置，better-scroll接口
        });

        this.foodsScroll.on('scroll',(pos) => {
          this.scrollY = Math.abs(Math.round(pos.y));//获取y值
        });
      },
      _calculateHeight() {
        let foodList = this.$refs.foodList;
        let height = 0;
        this.listHeight.push(height);
        for(let i=0; i<foodList.length; i++) {
          let item = foodList[i];
          height += item.clientHeight;
          this.listHeight.push(height);
        }
      }
    },
    components: {
      shopcart,
      cartcontrol
    },
  };
</script>

<style lang="stylus" rel="stylesheet/stylus">
  @import "../../common/stylus/mixin.styl"

  .goods
    display:flex
    position:absolute
    top:174px
    bottom:46px
    width:100%
    overflow:hidden
    .mennu-wrapper
      flex:0 0 80px
      width:80px
      background:#f3f5f7
      .menu-item
        display:table
        height:54px
        width:56px
        padding:0 12px
        line-height:14px
        &.current
          position:relative
          z-index:10
          margin-top:-1px
          background:#fff
          .text
            border-none()
        .icon
          display:inline-block
          font-weight:700
          vertical-align:top
          width:12px
          height:12px
          margin-right:2px
          background-size:12px 12px
          background-repeat:no-repeat
          &.decrease
            bg-image('decrease_3')
          &.discount
            bg-image('discount_3')
          &.guarantee
            bg-image('guarantee_3')
          &.invoice
            bg-image('invoice_3')
          &.special
            bg-image('special_3')
        .text
          display:table-cell
          vertical-align:middle
          border-1px(rgba(7,17,27,0.1))
          font-size:12px
    .foods-wrapper
      flex:1
      .title
        padding-left:14px
        height:26px
        line-height:26px
        border-left:2px solid #d9dde1
        font-size:12px
        color:rgb(147,153,159)  
        background:#f3f5f7
      .food-item
        display:flex
        margin:18px
        padding-bottom:18px
        border-1px(rgba(7,17,27,0.1))
        &:last-child
          border-none()
          margin-bottom:0
        .icon
          flex:0 0 57px
          margin-right:10px
        .content
          flex:1
          .name
            margin:2px 0 8px 0
            height:14px
            line-height:14px
            font-size:14px
            color:rgb(7,17,27)
          .desc,.extra
            line-height:10px
            font-size:10px
            color:rgb(147,153,159)
          .desc
            margin-bottom:8px
            line-height:13px
          .extra
            .count
              margin-right:12px
          .price
            font-weight:700
            line-height:24px
            font-size:24px
            .now
              margin-right:8px
              font-size:14px
              color:rgb(240,20,20)
            .old
              text-decoration:line-through
              font-size:10px
              color:rgb(147,153,159)
          .cartcontrol-wrapper
            position:absolute
            right:0
            bottom:12px

</style>
